No aftermarket for the Touring model unless you want to go with the coil-over kits you can get on eBay, but they are just about the same as OEM and are only manually adjustable. You are looking at about $2,000 for all four (exclusive of strut mount, strut bearing, bellows, etc.) I have a 1999 Q45t with 260,000 miles which I bought new at Orlando Infiniti in June 1999. I have needed struts for awhile, but kept putting it off because of the cost. Finally, I had to replace the right front one because I had a irritating noise from the strut bearing that was driving me crazy and made it embarrassing for anyone to ride in the car. So, I decided to replace the strut while I had everything apart. But boy did it need replaced, when i turned it upside down after removal, the rod just dropped right out. When you change the strut, you also want to change the stabilizer link (replaced those and the torsion bar rubber mounts at the same time). You can find the OEM struts at
http://www.infinitipartsnet.com in Scottsdale, AZ. The staff there are great. Next after replacing my right front, i knew i needed the rear ones because at high speed the rear of car floated back and forth dangerously. Boy was i lucky. the rear ones are nearly impossible to find. I also found them at the same place. A lot easier to change the rear ones than the front, primarily because of compressing the spring on the front i had to use two sets of spring compressors. Anyway, once i changed the rear ones it rode like a dream. Now, i am getting ready to order the left front as well as all the replacement parts. I also had to buy a used actuator as somehow i broke it changing the right front. be careful when reattaching it, dont over torque it or you could break the mount fitting. good luck!